Lleyton Hewitt will not dare to dream but a straight sets win over Spain's Feliciano Lopez at the Brisbane International on Thursday has brought the possibility of a final against 17-time grand slam champion Roger Federer tantalisingly close.

Hewitt rolled back the years with the 7-5, 6-3 victory over sixth seed Lopez, displaying his trademark fight before outclassing the Spaniard in the second set to move into the quarter-finals at Pat Rafter Arena.

It is the first time since 2009 that Hewitt has won back-to-back matches at his first ATP Tour event of the year and brings him within two matches of a possible final against Swiss great Federer.

The two 32-year-olds have met 26 times in their careers, with Federer holding an 18-8 record over Hewitt.

Hewitt's chances of once again taking on Federer were boosted on a day where French third-seed Gilles Simon joined Lopez on the tournament scrapheap following a shock loss to Romania's Marius Copil.

The world number 147 will be Hewitt's quarter-final opponent following his 7-5, 6-3 win over Simon, leaving Japan's Kei Nishikori as the only remaining seed in the Australian's side of the draw.

Nishikori will meet Croatia's Marin Cilic in the quarter-finals, but Hewitt refused to speculate on whether he could see a slightly easier path to Sunday's final.

"No. The guys that are in the quarter-finals are there for a reason," he said.

"Copil will give me all the challenge I need out there tomorrow ... he's got a big game, so I'm going to have to be ready for it."

Hewitt's win over the world number 28 came just two days after his first-round 6-3, 7-5 victory over teenage Australian qualifier Thanasi Kokkinakis.

The two-time grand slam winner had to dig himself out of an early hole against Lopez on Thursday night after being broken early, but won the opening set when his opponent committed back-to-back double faults.

"I was just trying to hang on in my service games through the first set and just stay only one break down," Hewitt said.

"In the end it worked perfectly because I was able to draw a couple double faults out of him and obviously got that break and then broke again at 6-5.

Mahut had made more of a name for himself in Brisbane as Federer's doubles partner at the tournament but kept former Wimbledon junior champion Chardy honest by clinching the second set.

But world number 50 Mahut, 31, could not sustain the pressure and buckled as Chardy emerged triumphant.

Federer has already booked his quarter-final berth where he will take on Australia's Marinko Matosevic for a place in the final four.

Australia's Sam Groth made hard work of beating French lucky loser Pierre-Hugues Herbert in the final match of the night.

The big-serving Victorian was given a great chance of making the quarter-finals when world number 20 Kevin Anderson withdrew from the tournament with a stomach virus in the build-up to the pair's second-round clash.

But world number 151 Herbert almost made the most of his unlikely chance at a quarter-final berth, with Groth needing two hours and 25 minutes to post an unconvincing 4-6, 7-6 (7-3), 7-6 (7-5) win.

Groth will meet Chardy on Friday for a place in the semi-finals.

In the late women's singles games on Thursday, fourth-seeded Jelena Jankovic beat fifth-seeded Angelique Kerber 6-7 (8), 6-3, 6-1 and world number two Victoria Azarenka took three sets to beat Switzerland's Stefanie Voegele 6-4, 6-7 (7), 6-1.